In the treatment of various spinal conditions, including the treatment of fractures, tumors and degenerative conditions, it is necessary to secure and stabilize the anterior column of the spine following removal of a vertebral body or part.
Following such removal made using a thoracotomy, thoracoabdominal or retroperitoneal approach, the normal anatomy is reconstructed using tricortical iliac crest or fibular strut grafts. It is then necessary to secure and stabilize the graft, desirably in such a manner as to permit rapid mobilization of the patient. Such objectives can be accomplished by a bone plate. However, to accomplish this service in the optimum manner, it is necessary that the plate be reasonably congruent with the bone to which it is applied, that it have as low a profile as possible, that it be firmly secured to the spinal column so that it is not torn out when the patient places weight and stress upon it and that it be capable of placement and fixation in a manner that is convenient for the surgeon.
In this context it is necessary to secure the plate to the spinal body and also, in some cases, to the graft. Conventionally, such attachment would be by the use of screws driven through screw holes in the plate into the bone. However, it is desirable in this instance not only to anchor the screw firmly in the spinal column in both the cortical and cancellous parts, but to have the screw firmly attached to the plate to prevent loosening of the screw/plate connection with changes in the bone.